Breakthrough time refers to the period of time that an individual or a team makes significant progress in achieving their goals. There are plenty of synonyms that can be used in place of breakthrough time, such as turning point, milestone, breakthrough moment, pivotal moment, breakthrough period, leap forward, progress period, landmark moment, achievement period and so on. These words convey a sense of positivity, progress, and achievement, and can be used in different situations to discuss a variety of scenarios such as personal growth, team success, scientific discoveries, and so on. Using these synonyms can add color and variety to your communication, and can help to emphasize the importance of significant progress.